diff --git a/sys/amd64/amd64/machdep.c b/sys/amd64/amd64/machdep.c
index 510c6d375a2..dbad85096a1 100644
--- a/sys/amd64/amd64/machdep.c
+++ b/sys/amd64/amd64/machdep.c
@@ -1367,7 +1367,7 @@ hammer_time(u_int64_t modulep, u_int64_t physfree)
 
 	thread0.td_kstack = (char *)physfree - kernphys + KERNSTART;
 	thread0.td_kstack_pages = kstack_pages;
-	kstack0_sz = thread0.td_kstack_pages * PAGE_SIZE;
+	kstack0_sz = ptoa(kstack_pages);
 	bzero(thread0.td_kstack, kstack0_sz);
 	cpu_thread_new_kstack(&thread0);
 	physfree += kstack0_sz;
diff --git a/sys/amd64/include/stack.h b/sys/amd64/include/stack.h
index 765a8e78dae..7d821348be0 100644
--- a/sys/amd64/include/stack.h
+++ b/sys/amd64/include/stack.h
@@ -12,7 +12,7 @@
 /* Get the current kernel thread stack usage. */
 #define GET_STACK_USAGE(total, used) do {				\
 	struct thread	*td = curthread;				\
-	(total) = td->td_kstack_pages * PAGE_SIZE;			\
+	(total) = ptoa(td->td_kstack_pages);				\
 	(used) = td_kstack_top(td) - (char *)&td;			\
 } while (0)
 
diff --git a/sys/arm/include/stack.h b/sys/arm/include/stack.h
index 6af9418aba4..f6bc67dbe77 100644
--- a/sys/arm/include/stack.h
+++ b/sys/arm/include/stack.h
@@ -68,7 +68,7 @@ void unwind_module_unloaded(struct linker_file *);
 /* Get the current kernel thread stack usage. */
 #define	GET_STACK_USAGE(total, used) do {				\
 	struct thread *td = curthread;					\
-	(total) = td->td_kstack_pages * PAGE_SIZE - sizeof(struct pcb);	\
+	(total) = ptoa(td->td_kstack_pages) - sizeof(struct pcb);	\
 	(used) = td->td_kstack + (total) - (char *)&td;			\
 } while (0)
 
diff --git a/sys/arm64/include/stack.h b/sys/arm64/include/stack.h
index b89019fbbec..0aa483e15e6 100644
--- a/sys/arm64/include/stack.h
+++ b/sys/arm64/include/stack.h
@@ -43,7 +43,7 @@ bool unwind_frame(struct thread *, struct unwind_state *);
 
 #define	GET_STACK_USAGE(total, used) do {				\
 	struct thread *td = curthread;					\
-	(total) = td->td_kstack_pages * PAGE_SIZE - sizeof(struct pcb);	\
+	(total) = ptoa(td->td_kstack_pages) - sizeof(struct pcb);	\
 	(used) = td->td_kstack + (total) - (char *)&td;			\
 } while (0)
 
diff --git a/sys/powerpc/include/stack.h b/sys/powerpc/include/stack.h
index 0fb9a929128..533ff0fa205 100644
--- a/sys/powerpc/include/stack.h
+++ b/sys/powerpc/include/stack.h
@@ -38,7 +38,7 @@ extern int end[];
 /* Get the current kernel thread stack usage. */
 #define	GET_STACK_USAGE(total, used) do {				\
 	struct thread *td = curthread;					\
-	(total) = td->td_kstack_pages * PAGE_SIZE - sizeof(struct pcb);	\
+	(total) = ptoa(td->td_kstack_pages) - sizeof(struct pcb);	\
 	(used) = td->td_kstack + (total) - (char *)&td;			\
 } while (0)
 
diff --git a/sys/riscv/include/stack.h b/sys/riscv/include/stack.h
index 7de9f05b567..5669dcda6c6 100644
--- a/sys/riscv/include/stack.h
+++ b/sys/riscv/include/stack.h
@@ -53,7 +53,7 @@ bool unwind_frame(struct thread *, struct unwind_state *);
 /* Get the current kernel thread stack usage. */
 #define	GET_STACK_USAGE(total, used) do {				\
 	struct thread *td = curthread;					\
-	(total) = td->td_kstack_pages * PAGE_SIZE - sizeof(struct pcb);	\
+	(total) = ptoa(td->td_kstack_pages) - sizeof(struct pcb);	\
 	(used) = td->td_kstack + (total) - (char *)&td;			\
 } while (0)